Wireless communication systems are occasionally prone to interruptions in service (i.e. a dropped call) and the location of holes in the coverage area where a user of a cellular radiotelephone or other telecommunications device is in an area where no network service is available. There are many causes for these service dropout areas, including blocked radio paths, being located in remote areas with no base stations or areas where there are substantial disturbances (e.g. mountains, large buildings, being underground, or being shielded from radio signals), hardware or software problems in either the base station or radiotelephone, etc. In such cases, these interruptions in coverage can result in a user not being able to place a call or can result in a terminated call when entering such no-coverage areas. As a result, a user will have no indication of what to do to obtain or regain service and typically endeavors to make repeated attempts to re-establish a connection, which can often be fruitless. This is inconvenient and annoying to a user of the communication system. Moreover, since many people use such devices specifically to be able to request assistance in an emergency situation (i.e. when making an emergency E911 call), an inability to obtain network coverage significantly reduces the utility of the device.
In the case where a user enters a no-coverage area, there are several techniques to reconnect a dropped call. In the most obvious case, the user can reinitiate the call after moving to a new location. However, this is inconvenient and annoying to the user. More advanced solutions have called for the radiotelephone and/or network to automatically work to reconnect the call. In one solution, as a radiotelephone is leaving a coverage area of a base station, the network will initiate a handoff procedure. If this handoff procedure does not work, the radiotelephone initiates its own handoff procedure by seeking out a second base station (such as from its neighboring cell list) for handoff. Another solution is for the network to initiate re-connection of a dropped call by calling back the mobile station to establish a new connection. This is most applicable to emergency call situations. However, these solutions all require that there be some coverage from some base station with which the radiotelephone can establish two-way contact. None of these solutions recognize the problem associated with the radiotelephone being outside of a coverage area of any base station. In addition, none of these solutions address the problem of obtaining service when a radiotelephone is initially turned on in a no-coverage area.
Accordingly, what is needed is a method and apparatus to obtain service in a no-coverage area of a radiotelephone communication system. In particular, techniques are needed for a user to locate where service can be obtained when there is no two-way communication with any base station. Specifically, the method and apparatus would allow the user to determine a known point for connection to a network when the radiotelephone is outside of a network coverage area, either through moving out of a coverage area or starting within a no-coverage area.